media: ddbridge: add macros to handle IRQs in nibble and byte blocks

Currently, each IRQ requires one IRQ_HANDLE() line to call each IRQ
handler that was set up. Add a IRQ_HANDLE_NIBBLE() and IRQ_HANDLE_BYTE()
macro to call all handlers in blocks of four (_NIBBLE) or eight (_BYTE)
handlers at a time, to make this construct more compact.

Picked up from the upstream dddvb-0.9.33 release.

Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>